Electric stapler and stapler trigger circuit



R. M. BELTRAMO ELECTRIC STAPLER AND STAPLER TRIGGER CIRCUI Oct. 3, 1967 Filed July 20, 1964 United States Patent 3,345,546 ELECTRIC STAPLER AND STAPLER TRIGGER CIRCUIT Renaldo M. Beltramo, Royal Oak, Mich., assignor, by

mesne assignments, to Michigan Bank, National Association, a national banking association Filed July 20, 1964, Ser. No. 383,857 16 Claims. (Cl. 318-132) ABSTRACT OF THE DISCLOSURE An electronic circuit for triggering an electrical stapling device with means for varying the power to the stapling device and with means for providing only one actuation of the stapling device for each actuation of the trigger controlling the electronic circuit.

The present invention relates to electrical stapling devices, and also to electronic circuits capable of triggering such electrical stapling devices.

The present invention pertains to a portable hand actuated electrical stapling device which is actuable by means of a novel electronic trigger circuit. In general, the electrical stapling device utilizes solenoid action for driving staples and in combination with the electronic trigger circuit includes means whereby the driving power can be selectively varied to accommodate the driving of the staples through materials having diiferent hardness, thickness, etc. Therefore, it is a general object of this invention to provide a novel improved electrical stapling device.

It is another object of this invention to provide a novel electronic trigger circuit for providing a trigger pulse capable of actuating the electrical stapling device of the present invention.

It is another object of this invention to provide in combination an electrical stapling device including an electronic trigger circuit with means for selectively varying the power to the electrical stapling device in order to accommodate different driving conditions.

It is another general object of this invention to provide a novel electronic circuit for providing a pulsed output.

Other objects, features, and advantages of the present invention will become apparent from the subsequent description and the appended claims, taken in conjunction with the accompanying drawings, in which:

FIGURE 1 is a side elevational view with some parts shown in section, and with some parts shown partially broken away of an electrical stapling device of the present invention;

FIGURE 2 is a top elevational view of the electrical stapling device of FIGURE 1; and

FIGURE 3 is a schematic diagram of a novel electronic trigger circuit for providing the trigger pulse for actuating the electrical stapling device of FIGURES 1 and 2.

Referring now to FIGURE 1, the electrical stapling device is generally indicated by the numeral and includes a tubular, hollow, handle section 12 which is of a two-piece, longitudinally split symmetrical construction and which, when assembled, comprises a generally longitudinally extending gripping portion 14, which is specifically designed to facilitate gripping by hand, and a portion 16 which depends from the rearward end of the gripping portion 14. A tubular, generally cylindrical solenoid housing assembly 18 is attached to the forward end of the gripping portion 14 and has its central axis extending generally transversely to the direction of extension of the gripping portion 14. The solenoid assembly 18 includes a cylindrical member 20 which is attached such as lug 22, at one side to the forward end of the gripping portion 14. A cap 24 is removably secured to the top of the cylindrical member 22 and a nose assembly 26 is removably secured to the bottom of the cylindrical member 20. A coil member 28 is located within the cylindrical member 20 against a radial shoulder 32 at its lower end and is axially secured there by a retaining washer assembly 30. The coil 28 has a central, generally cylindrical aperture 34 which is in coaxial alignment with a tubular, generally cylindrically shaped guide portion 36 which is integral with and depends from an axially inwardly offset flange portion 37 of the cap 24.

A plunger assembly 38 has a cylindrical plunger section 40 which is movable, reciprocably matably within the bore 34 and which has at its upper end an aperture 42 for receiving the tubular guide portion 36. The aperture 42 is provided to be a close fit relative to the guide portion 36 for a purpose to be described. The upper extremity of the plunger portion 40 terminates in a radially outwardly extending flange 43; a conically shaped coil spring 44 has its enlarged end in engagement with the washer retaining assembly 30 and has its smaller end in engagement with the flange 43 and is normally under a precompression to thereby urge the plunger portion 40 and hence the plunger assembly 38 to its uppermost position. A stop washer 46, of rubber or the like, is secured to the flange portion 37 of the cap 24 and is engageable by the flange 43, of the plunger portion 40 with the plunger portion 40 in its uppermost position, at which position the lower extremity of plunger portion 40 extends partially within the bore 34 in coil 28.

A generally flat, rectangular blade 48, as shown in FIGURE 1, is located in a slot in the lower extremity of plunger portion 40 and is secured there by means of a pin 50. The nose assembly 26 includes an annular, stop member 52, of rubber or the like, which is located coaxially with the bore 34 in coil 28 and is engageable with the lower extremity of the plunger portion 40 and hence determines the downwardmost travel of the plunger assembly 38. A magazine assembly 56, of a conventional structure for holding a plurality of staples, extends generally longitudinally and is comprised of a lower plate structure 59 and a generally U-sectioned upper housing 61. The upper housing 61 has its rearward end connected to the depending portion 16 of the handle section 12 by means of a pivot assembly 57 and has its forward portion welded or otherwise connected to the nose assembly 26. The lower plate structure 59 is pivotally connected at its rearward end to the upper housing 61 via the pivot assembly 57 for pivotal movement about the point 67. A latch structure 58 secured to the upper housing 61 is operable with the plate structure 59 to permit its selective engagement or release of the plate structure 59. For loading staples into magazine 56 the latch structure 58 is actuated to release the lower plate 59; the lower plate 59 is pivoted downwardly in clearance relavia a lug structure,

tion with the housing 61 whereby staples can be loaded therein and is then returned and latched to the housing 61. A fiat, transversely extending plate 63 is fixed to the forward end of the fiat plate 59 and is movable therewith and defines with a confronting slot 65 in the nose assembly 26 an aperture portion 54. The forward end of the magazine assembly 56 communicates with the aperture portion 54 and is constructed, in a conventional manner, to feed the staples one at a time into the aperture portion 54. The nose assembly 26 has an aperture extending therethrough in communication with and in coaxial alignment with the bore 34 of the coil 28 and with the aperture portion 54. The aperture portion 54 is provided to have a cross section substantially identical to the cross section of the blade 48 whereby it permits QB travel of the blade 48 therethrough and acts as a guide therefor.

The coil 48 and plunger assembly 38 are constructed to act as a solenoid whereby electrical energization of the coil 28 causes the plunger assembly 38 to move downwardly through the bore 34 until the plunger portion 40 engages the stop member 52 with the blade segment 48 moving through the aperture in the nose assembly 26 including the aperture portion 54. On deenergization of the coil 28 the spring 44, now additionally compressed, causes the plunger assembly 38 to return to its original, upper position.

'The magazine assembly 56 can be of a conventional construction well known in the art, and hence the specific details thereof have been omitted for purposes of simplicity. The latch 58 likewise can be of a construction well known in the art.

In the position as shown in FIGURES 1 and 2, with the magazine assembly 56 loaded with staples, a single staple will be located within the aperture portion 54 such that on energization of the coil '28 solenoid action will cause the plunger assernbely 38 to move downwardly moving the blade 48 into contact with the staple in the aperture portion 54 severing that staple from the remaining group of staples to which it is attached and forcing the severed staple into the object or objects to be stapled. The handle portion 42 has at its forward lower end a trigger assembly'otl which is mounted for pivotal movement and is connected with a conventional microswitch 62 which, upon actuation, causes energization of the coil 28 in a manner to be presently described.

A variable resistance member 6 1 is located in the cap 24 and is operable by means of a rotatable dial 66 such that by selectively changing the position of the dial 66 the resistance of the member 64 is changed. In a manner to be described, this change in resistance provides a corresponding change in the power delivered to the coil 28. Thus the force applied to the plunger *assembly 38 by the coil 28 will be varied, hence varying the force applied to the staple. Thus means are provided whereby the force applied to the staple by the electric stapling device 10 can be selectively varied by the individual operator 'to suit the particular conditions. After actuation of the coil 28 and movement of the plu-nger'assembly 38 to its downwardmo'st position, subsequent de'cnergization of the coil 28 results in the spring '44 returning the plunger assembly 33 to its uppermost position. As the aperture 42 at the upper end or" the plunger portion 40 moves over the guide portion 36, the air trapped within the volume of the aperture 42 acts as a d'ampenerto reduce the shock or impact of the plunger portion 40 against the stop washer 46. Note that the length of the blade 48 is provided such that with the plunger portion 40 in contact with stop member 52 the end of the blade 48 will be located substantially at the lower extremity of the nose assembly 26 thereby assuring that the staple will "be driven its full length. The circuitry for driving the energizing coil 28 is located within the hollow handle section 12 and can be energized by means of an electric cord which is extensible through a tubular, flexible fitting 68 located generally at the upper, rearward end of the gripping portion 14.

In operation, it is desirable that the coil 28 be actuated only one time for each actuation of trigger 60, and as previously noted, manipulation of the rotatable dial 66 provides means for adjusting the power to and hence the power from the coil 28. The latter functions are performed by the electronic circuit shown in FIGURE '2 3 and generally indicated by the numeral 100. The circuit 100 is located within the handle section 12 and is connected to a source of alternating potential by means of a pair of conductors 102, 104 which extend through the connector 68. A pair of resistors R1 and R2, which make up a voltage dividing network, having a conductor 106 connected therebetween, are serially connected between the conductors 102 and 104. A pulse generating circuit is connected between conductors 102 and 106 and includes a silicon controlled rectifier -SCR1 whichhas'its cathode K1 connected directly to the conductor 102, its gate G1 connected to the conductor 102 via a resistor R3 and its anode A1 connected to the conductor 11% via the primary winding P of a transformer T. The gate G1 is also connected to the conductor .106 by means of a series circuit including a fixed resistor R4, a variable resistor R5 and the primary winding P. The variable resistor R5 corresponds to the resistor 64 previously described. With the circuit described thus far connected to a source of alternating potential via the conductors 102 and 104, the S'CR1 will be conductive during alternate half cycles when the conductor 104 is positive relative to conductor 102. The portion of that positive half cycle over which the SCRl will be conductive will be determined by its bias condition and by that time when the gate to cathode current is of sufficient magnitude to render the anode-cathode circuit of the SCRI conductive. Since the potential applied to the gate-cathode circuit of SCRl is sinusoidal, the point on the positive half cycle at which the'current through the gate-cathode circuit is of sufiicient magnitude to render 'SCRl conductive can be varied by varying the resistor R5 (6 4). The resistors R4 and R5 generally determine the magnitude of the gate to cathode current with resistor R3 acting as a shunt to raise the gate-to-firc current of S'CRI to a preselected level.

When the SCR-l is turned on, a substantially low resistance or short circuit path is provided through its anode-cathode circuit to the primary P of transformer T; the rapid increase in current through the primary P as a result of SCRI being switched on results in an induced voltage or trigger pulse in a secondary winding 5 of the transformer T of a short width or duration relativev to the period of the half cycles of the alternating current source "for a purpose to be seen. The secondary winding S has one end connected to conductor 102 and has its opposite end connected to the anode of a diode D. The cathode of the diode D is connected to one terminal 108 of the switch 62 (previously described) which has its other terminal 110 connected directly to the conductor 102. The switch 62 has a movable contact 112 which is connected for alternate movement between the terminals 108 and 110 and is normally maintained in electrical contact with the terminal 110, as shown in FIGURE 3. A capacitor Chas one end connected to the movable contact 112 and has its opposite end connected to a .gate electrode G2 of a second silicon controlled rectifier SCRZ with the gate electrode G2 connected to conductor 102 via a resistor R6. The SCRZ has its cathode electrode K2 connected directly to the conductor .102 and has its anode electrode A2 serially :connected to the coil 28 and to the conductor 104. With the switch 62 in the position as shown, the pulses provided at the secondary S at the transformer T as the result of the periodic conduction of the SCRl are ineifective to initiate conduction of the SCR2. At the same time there is no current flowing between the ,gate G2 and cathode K2 whereby the SCRZ can be fired; hence no power is being delivered to the coil 28. In order toactuate the SCR2 and to thereby energize the coil 28 to perform a stapling operation, the switch '62 is actuated to move the contact 112 to its alternate position in engagement with the terminal 108. At this time the pulses at the secondary S :as a result of the periodic conduction-of =SC-R]. are transmitted through the diode D, through the capacitor C and hence provide current through the gate "G2 .to the cathode K2. The resistor R6 acts to limit the current through the gatecatho'de circuit G2, K2. Duringthe first pulse the capacithe gate-cathode circuit tor C is in an uncharged condition and instantaneously actsas a short circuit permitting suificient current to pass to render SCR2 conductive. However, the RC charge time constant of the circuit of capacitor C is selected to be relatively short such that the capacitor C charges rapidly during that first pulse; for the purposes of charging capacitor C and firing SCR2 the diode D provides a low forward impedance; on alternate negative half cycles, however, and for purposes of discharging capacitor C the diode D provides a high back impedance. Thus, on alternate, negative half cycles the capacitor C discharges only slightly. Upon occurrence of the positive trigger pulses at the secondary S succeeding the first trigger pulse the capacitor C will be substantially charged and only a small charge current will flow which is insufiicient to again trigger SCR2. When SCR2 fires, a relatively low impedance or short circuit path is provided between the anode A2 and the cathode K2 hence directly connecting the coil 28 across the conductors 102 and 104 thereby causing energization of the coil 23 and hence causing the plunger assembly 38 to move downwardly to drive or set a staple. Assuming that the trigger 60 is not released after occurrence of the pulse energizing the coil 28 and moving the plunger assembly 38 downwardly, no further current flows to coil 28 during the following negative half cycle and the spring 44 initiates the return of the plunger assembly 38 to its upper position. As previously described, as the next positive, trigger pulse occurs at the secondary S at the transformer T the charge current to the capacitor C and hence to G2, K2 will be of a magnitude insufiicient to cause firing of the SCR2. Thus, upon actuation of the switch 62 by means of the trigger 60, only a single energizing pulse will be caused to be delivered to the coil 28 and hence only one fastener or staple can be driven for each such actuation of the trigger 60. In order to drive another staple, the trigger 60 is released whereby the movable contact 112 moves back to its alternate or normal position in engagement with the terminal 110. In this position the capacitor C has a discharge circuit with a relatively short RC time constant and the capacitor C can completely discharge quickly. To set the next staple the trigger 60 is again actuated to again move the movable contact 112 of the switch 62 to its alternate position in engagement with the contact 108 whereby a second energizing pulse will be transmitted through the anode-cathode circuit of SCR2 and through the coil 28 to drive a second staple. The value of the fixed resistor R4 is selected such that. with the resistor R5 having a zero value, the SCRI will conduct at the earliest selected point in the cycle in the positive half cycle of the alternating current potential. The selected relative to the values of R4 and R3 such that the SCRl will be triggered at approximately 90 in the positive half cycle of the alternating current from the source. The point at which condition of the SCRl is initiated in general determines the length of the half cycle over which the SCR2 conducts. Hence, by varying the point of initiation of conduction of SCRl by means of the variable resistor R5 that portion of the positive half cycle over which the SCR2 will conduct can be varied. Thus the power delivered to the coil 28 can be varied by manipulation of the resistor R5. As shown in FIG- URE 2, an appropriate scale can be incorporated with the dial 66, thereby providing the operator with visual indication of the relative power selected between low and high points.

Since trigger pulses are continuously being generated it is possible to move contact 112 into engagement with contact 108 during the occurrence of one of these pulses to actuate the SCR2. By providing the pulses to be of a relatively short width such actuation can occur at any point along the width of a pulse with only slight variation resulting in the width of that portion of the positive half cycles over which SCR2 conducts.

maximum value of R5 is While it Will be apparent that the preferred embodiment of the invention disclosed is well calculated to fulfill the objects above stated, it will be appreciated that the invention is susceptible to modification, variation and change without departing from the proper scope or fair meaning of the subjoined claims.

What is claimed is:

1. A portable electrical fastening device operable from a source of alternating potential, comprising: plunger assembly means mounted for movement between first and second positions for driving a fastener with a driving force upon movement from said first position to said second position, coil means operatively connected with said plunger assembly for moving said plunger assembly means from said first position to said second position upon energization by an energizing pulse from the source, first circuit means for producing said energizing pulse and for transmitting said energizing pulse to said coil means responsively to a trigger pulse, second circuit means for generating said trigger pulse, and switch means selectively actuable for electrically connecting said second circuit means to said first circuit means whereby said energizing pulse is produced, said first circuit means with said switch means actuated at first responsive to a said trigger pulse for producing said energizing pulse and later responsive to a said trigger pulse for preventing production of said energizing pulse.

2. A portable electrical fastening device operable from a source of alternating potential, comprising: plunger assembly means mounted for movement between first and second positions for driving a fastener with a driving force upon movement from said first position to said second position, coil means operatively connected with said plunger assembly for moving said plunger assembly means from said first position to said second position upon energization by an energizing pulse from the source, first circuit means for producing said energizing pulse and for transmitting said energizing pulse to said coil means responsively to a trigger pulse, second circuit means for generating a plurality of trigger pulses from the source and switch means selectively actuable for electrically connecting said second circuit means to said first circuit means whereby said energizing pulseis produced, said first circuit means including control means for producing said energizing pulse for only a single actuation of said plunger assembly means from said first position to said second position for each actuation of said switch means, said control means including storage circuit means for preventing the production of said energizing pulse upon attainment of a charge of a preselected magnitude and being chargeable responsively to said trigger pulses and with said switch means actuated having a charge circuit with a short charge time and a discharge circuit with a long discharge time relative to the period of said trigger pulses, the time for attainment of said charge of a preselected magnitude being no greater than the time for a single actuation of said plunger assembly means.

3. A portable electrical fastening device operable from a source of alternating potential, comprising: plunger assembly means mounted for movement between first and second positions for driving a fastener with a driving force upon movement from said first position to said second position, coil means operatively connected with said plunger assembly for moving said plunger assembly means from said first position to said second position upon energization by an energizing pulse from the source, first circuit means for producing said energizing pulse and for transmitting said energizing pulse to said coil means responsively to a trigger pulse, second circuit means for generating a plurality of trigger pulses from the source and switch means selectively actuable for electrically connecting said second circuit means to said first circuit means whereby said energizing pulse is produced, said first circuit means including control means for producing said energizing pulse for only a single actuation of said including said selected half cycle,

plunger assembly means from said first position to said I with said switch means actuated having a charge circuit with a short charge time and a discharge circuit with a long discharge time relative to the period of said trigger pulses and with said switch means deactuated having a different discharge circuit with a substantially shorter discharge time than said first mentioned discharge circuit, the time for attainment of said charge of a preselected magnitude being no greater than the time for a single actuation of said plunger assembly means.

4. A portable electrical fastening device operative from a source of alternating potential comprising: a plunger assembly means mounted for movement between first and second positions for driving a fastener with a driving force upon movement from said first position to said second position, coil means operatively connected with said plunger assembly for moving said plunger assembly means from said first position to said second position upon energization by an energizing pulse, first circuit means for producing said energizing pulse and for transmitting said energizing pulse to said coil means responsively to a trigger pulse, second circuit means for continuously generating said trigger pulses at a rate determined by the frequency of said source, and switch means selectively actuable between a first condition electrically connecting said first and second circuit means and a second condition electrically disconnecting said first and second circuit means, said first circuit means incuding control means for producing only a single energizing pulse for each actuation of said switch means to said first condition, said control means including storage circuit means for preventing the production of said energizing pulse upon attainment of a charge of a preselected magnitude and being chargeable responsively to said trigger pulses and with said switch means in said first condition actuating a charge circuit with a short charge time and a discharge circuit with a long discharge time relative to the period of said trigger pulses and with said switch means in said second condition actuating a different discharge circuit having a substantially shorter discharge time than said first mentioned discharge circuit.

5. A portable electrical fastening device operative from a source of alternating potential, comprising: plunger assembly means mounted for movement between first and second positions for driving a fastener with a driving force upon movement from said first position to said second position, coil means operatively connected with said plunger assembly for moving said plunger assembly means from .said first position to said second position ,upon energization by an energizing pulse, first circuit means for producing said energizing pulse and for transmitting said energizing pulse to said coil means responsively to a trigger pulse, said first circuit means including means operatively connected with the source and said coil for electrically connecting said coil means to the source during a selected half cycle with said energizing pulse being transmitted from the source during said selected half cycle and for substantially that portion of said selected half cycle immediately succeeding said trigger pulse, second ciriuit means for continuously generating said trigger pulses responsively to half cycles of the source said second circuit means including means selectively operable for varying the time of occurrence of said trigger pulses during said half cycles and including said selected half cycle, and switch means selectively actuable between a first condition electrically connecting said first and second circuit means and a second condition electrically disconnecting said first and second circuit means, said first circuit means including control means for producing only a single energizing pulse for each actuation of said switch means to said first condition, said control means including storage circuit means for preventing the production of said energizing pulse upon attainment of a charge of a preselected magnitude and being chargeable responsively to said trigger pulses and With said switch means in said first condition actuating a charge circuit with a short charge time and a discharge circuit with a long discharge time relative to the period of said trigger pulses and with said switch means in said second condition actuating a different discharge circuit having a substantially shorter discharge time than said first mentioned discharge circuit.

6. A portable electrical fastening device operative from a source of alternating potential, comprising: plunger assembly means mounted for movement between first and second positions for driving a fastener with a driving force upon movement from said first position to said second position, coil means operatively connected with said plunger assembly for moving said plunger assembly means from said first position to said second position upon energization by an energizing pulse, first circuit means for producing said energizing pulse and for transmitting said energizing pulse to said coil means responsively to a trigger pulse, said first circuit means including a silicon controlled rectifier having anode, cathode and gate electrodes with said anode and cathode electrodes serially connecting said coil means to the source during a selected one of alternate half cycles in response to said trigger pulse at said cathode and gate electrodes with said energizing pulse being transmitted from the source during said selected half cycle and for substantially that portion of said selected half cycle immediately succeeding said trigger pulse, second circuit means for continuously generating said trigger pulses responsively to said alternate half cycles of the source, said second circuit means including means selectively operable for varying the time of occurrence of trigger pulses during said alternate half cycles and including said selected half cycle, and switch means selectively actuable between a first condition electrically connecting said first and second circuit means and a second condition electrically disconnecting said first and second circuit means, said first circuit means including control means for producing a selected number of energizing pulses for each actuation of said switch means to said first condition, said control means including a capacitor serially connected with said gate electrode and said switch means and being chargeable responsively to said trigger pulses to a preselected magnitude for reducing the amplitude of the current through said gate and cathode electrodes for preventing conduction of said anode and cathode electrodes on said alternate half cycles and with said switch means in said first condition actuating a charge circuit for said capacitor with a short charge time and a discharge circuit with a long discharge time relative to the period of said trigger pulse and with said switch means in said second condition actuating a different discharge circuit having a substantially shorter discharge time than said first mentioned discharge circuit.

7. A portable electrical fastening device operative from a source of alternating potential, comprising: plunger assembly means mounted for movement between first and second positions for driving a fastener with a driving force upon movement from said first position to said second position, coil means operatively connected with said plunger assembly for moving said plunger assembly means from said first position to said second position upon energization by an energization pulse, first circuit means for producing said energizing pulse and for transmitting said energizing pulse to said coil means responsively to a trigger pulse, said first circuit means including a silicon controlled rectifier having anode, cathode, and gate electrodes with said anode and cathode electrodes serially connecting said coil means to the source during a selected one of alternate half cycles in response to said trigger pulse at said cathode and gate electrodes with said ener- 9 gizing pulse being transmitted from the source during said selected half cycle and for substantially that portion of said selected half cycle immediately succeeding said trigger pulse, second circuit means for continuously generating said trigger pulses responsively to said alternate half cycles of the source, said second circuit means including a silicon controlled rectifier having anode, cathode, and gate electrodes with said anode and cathode electrodes connected to the source for conduction during said alternate half cycles, said second circuit means including circuit means connecting said gate and cathode electrodes across the source and comprising a variable resistor selectively variable for varying the time during said alternate half cycles when the current through said gate and cathode electrodes attains the magnitude rendering said anode and cathode electrodes conductive, and switch means selectively actuable between a first condition electrically connecting said first and second circuit means and a second condition electrically disconnecting said first and second circuit means, said first circuit means including control means for producing a selected number of energizing pulses for each actuation of said switch means to said first condition, said control means including a capacitor serially connected with said gate electrode and said switch means and being chargeable responsively to said trigger pulses to a preselected magnitude for preventing flow of suflicient current through said gate and cathode electrodes for preventing conduction of said anode and cathode electrodes on said alternate 'half cycles and with said switch means in said first condition actuating a charge circuit for said capacitor with a short charge time and a discharge circuit with a long discharge time relative to the period of said trigger pulse and with said switch means in said second condition actuating a different discharge circuit having a substantially shorter discharge time than said first mentioned discharge circuit.

8. An electronic circuit for providing a pulsed output comprising: first circuit means for producing an output pulse responsively to a trigger pulse, second circuit means for continuously generating said trigger pulses, switch means selectively actuable for electrically connecting said second circuit means to said first circuit means whereby said output pulse is produced, and timing means connected to said first and second circuit means and responsive to said trigger pulses for preventing actuation of said first circuit means by successive ones of said trigger pulses after a preselected time interval.

9. An electronic circuit for providing a pulsed output comprising: first circuit means for producing an output operable from a source of alternating potential pulse responsively to a trigger pulse, second circuit means for continuously generating said trigger pulses from the source, switch means selectively actuable for electrically connecting said second circuit means to said first circuit means whereby said output pulse is produced, and timing means connected to said first and second circuit means and responsive to said trigger pulses for preventing actuation of said first circuit means by successive ones of said trigger pulses after a preselected time interval, said timing means including storage circuit means for preventing the production of said output pulse upon attainment of a charge of a preselected magnitude and being charge able responsively to said trigger pulses and with said switch means actuated having a charge circuit with a short charge time and a discharge circuit with a long discharge time relative to the period of said trigger pulses, the time for attainment of said charge of a preselected magnitude being no greater than said preselected time interval.

10. An electronic circuit for providing a pulsed output operable from a source of alternating potential comprising: first circuit means for producing an output pulse responsively to a trigger pulse, second circuit means for continuously generating said trigger pulses from the source, switch means selectively actuable for electrically connecting said second circuit means to said first circuit means whereby said output pulse is produced, and timing means connected to said first and second circuit means and responsive to said trigger pulses for preventing actuation of said first circuit means by successive ones of said trigger pulses after a preselected time interval, said timing means including storage circuit means for preventing the production of said output pulse upon attainment of a charge of a preselected magnitude and being chargeable responsively to said trigger pulses and with said switch means actuated having a charge circuit with a short charge time and a discharge circuit with a long discharge time relative to the period of said trigger pulses, and with said switch means deactuated having a different discharge circuit with a substantially shorter discharge time than said first mentioned discharge circuit, the time for attainment of said charge of a preselected magnitude being no greater than said preselected time interval.

11. An electronic circuit for providing a pulsed output comprising: first circuit means for producing an output pulse responsively to a trigger pulse, second circuit means for continuously generating said trigger pulses, switch means selectively actuable for electrically connecting said second circuit means to said first circuit means whereby said output pulse is produced, and means for selectively shifting the phase of said trigger pulses, said first circuit means including means varying the magnitude of said output pulse responsively to the selected variations in the phase of said trigger pulses and timing means connected to said first and second circuit means and responsive to said trigger pulses for preventing actuation of said first circuit means by successive ones of said trigger pulses after a preselected time interval, said timing means including energy storage means for preventing actuation of said first circuit means upon attainment of a charge of a preselected magnitude and circuit means for connecting said trigger pulses to said storage means upon actuation of said switch means whereby said storage means attains said charge by said trigger pulses.

12. An electronic circuit operable from a source of alternating current for providing a pulsed output comprising: first circuit means for producing an output pulse from the source during a selected one of alternate half cycles of the source responsively to a trigger pulse with said output pulse being transmitted from the source for substantially that portion of said selected half cycle immediately succeeding said trigger pulse, second circuit means for continuously generating said trigger pulses during and responsively to said alternate half cycles, said second circuit means including means for selectively varying the time of occurrence of said trigger pulse during said alternate half cycles, and switch means selectively actuable for electrically connecting said second circuit means to said first circuit means whereby said output pulse is produced and timing means connected to said first and second circuit means and responsive to said trigger pulses for preventing actuation of said first circuit means by successive ones of said trigger pulses after a preselected time interval.

13. An electronic circuit operable from a source of alternating potential for providing a pulsed output comprising: first circuit means for producing an output pulse in a selected one of alternate half cycles from the source responsively to a trigger pulse, said first circuit means including a controlled unidirectional conductive device connected to the source for transmitting said output pulse therefrom during said selected half cycle responsively to said trigger pulse for substantially that portion of said selected half cycle immediately succeeding said trigger pulse, second circuit means for continuously generating said trigger pulses, switch means selectively actuable for electrically connecting said second circuit means to said first circuit means whereby said output pulse is produced, and timing means connected to said first and second circuit means and responsive to said trigger pulses for preventing actuation of said first circuit means by successive ones of said trigger pulses after a preselected time interval, said timing means including energy storage means for preventing actuation of said first circuit means upon attainment of a charge of a preselected magnitude and circuit means for connecting said trigger pulses to said storage means upon actuation of said switch means whereby said storage means attains said charge by said trigger pulses.

14. An electronic circuit operable from a source of alternating potential for providing a pulsed output comprising: first circuit means for producing an output pulse in a selected one of alternate half cycles from the source responsively to a trigger pulse, said first circuit means including a silicon controlled rectifier having anode, cathode and gate electrodes with said anode and cathode electrodes generally connected across the source for transmitting said output pulse therefrom during said selected half cycle in response to said trigger pulse at said cathode and gate electrodes with said output pulse being transmitted from the source for substantially that portion of said selected half cycle immediately succeeding said trigger pulse, second circuit means for continuously generating said trigger pulses, switch means selectively actuable for electrically connecting said second circuit means to said first circuit means whereby said output pulse is produced, and timing means connected to said first and second circuit means and responsive to said trigger pulses for preventing actuation of said first circuit means by successive ones of said trigger pulses after a preselected time interval, said timing means including energy storage means for preventing actuation of said first circuit means upon attainment of a charge of a preselected magnitude and circuit means for connecting said trigger pulses to said storage means upon actuation of said switch means whereby said storage means attains said charge by said trigger pulses.

15. An electronic circuit operable from a source of alternating potential for providing a pulsed output comprising: first circuit means for producing an output pulse in a selected one of alternate half cycles from the source responsively to a trigger pulse, said first circuit means including a silicon controlled rectifier having anode, cathode and gate electrodes with said anode and cathode electrodes generally connected across the source for transmitting said output pulse therefrom during said selected half cycle in response to said trigger pulse at said cathode and gate electrodes with said output pulse being transmitted from the source for substantially that portion of said selected half cycle immediately succeeding said trigger pulse, second circuit means for continuously generating said trigger pulses, switch means selectively actuable between a first condition electrically connecting said first and second circuit means and a second condition electrically disconnecting said first and second circuit means, said first circuit means including control means for producing only a selected number of output pulses for each actuation of said switch means to said first condition, said control means including a capacitor serially connected with said gate electrode and said switch means and being chargeable responsively to said trigger pulses to a preselected magnitude for reducing the amplitude of the current through said gate and cathode electrodes for preventing conduction of said anode and cathode electrodes on said alternate half cycles and with said switch means in said first condition actuating a charge circuit for said capacitor with a short charge time and a discharge 'circuit with a long discharge time relative to the period of said trigger pulses and with said switch means in said second condition actuating a different discharge circuit having a substantially shorter discharge time than said first mentioned discharge circuit.

16. An electronic circuit operable from a source of alternating potential for providing a pulsed output comprising: first circuit means for producing an output pulse in a selected one of alternate half cycles from the source responsively to a trigger pulse, said first circuit means including a silicon controlled rectifier having anode, cathode and gate electrodes with said anode and cathode electrodes generally connected across the source for transmitting said output pulse therefrom during said selected half cycle in response to said trigger pulse at said cathode and gate electrodes with said output pulse being transmitted from the source for substantially that portion of said selected half cycle immediately succeeding said trigger pulse, second circuit means for continuously generating said trigger pulses, switch means selectively actuable between a first condition electrically connecting said first and second circuit means and a second condition electrically disconnecting said first and second circuit means, said first circuit means including control means for producing only a selected number of output pulses for each actuation of said switch means to said first condition, said control means including a capacitor serially connected with said gate electrode and said switch means and being chargeable responsively to said trigger pulses to a preselected magnitude for reducing the amplitude of the current through said gate and cathode electrodes for preventing conduction of said anode and cathode electrodes on said alternate half cycles and with said switch means in said first condition actuating a charge circuit for said capacitor with a short charge time and a discharge circuit with a long discharge time relative to the period of said trigger pulses and with said switch means in said second condition actuating a ditferent discharge circuit having a substantially shorter discharge time than said first mentioned discharge circuit, said second circuit means including a transformer having its primary winding connected for conducting the current through said cathode and anode electrodes and having a secondary winding for providing said trigger pulses therefrom.

References Cited UNITED STATES PATENTS 3,179,866 4/1965 Doyle et al. 3,278,101 11/1966 Hatazaki 227131 X 3,267,337 8/1966 Doyle et al.

MILTON O. HIRSHFIELD, Primary Examiner.

LEE T. HIX, Examiner. 

8. AN ELECTRONIC CIRCUIT FOR PROVIDING A PULSED OUTPUT COMPRISING: FIRST CIRCUIT MEANS FOR PRODUCING AN OUTPUT PULSE RESPONSIVELY TO A TRIGGER PULSE, SECOND CIRCUIT MEANS FOR CONTINUOUSLY GENERATING SAID TRIGGER PULSES, SWITCH MEANS SELECTIVELY ACTUABLE FOR ELECTRICALLY CONNECTING SAID SECOND CIRCUIT MEANS TO SAID FIRST CIRCUIT MEANS WHEREBY SAID OUTPUT PULSE IS PRODUCED, AND TIMING MEANS CONNECTED TO SAID FIRST AND SECOND CIRCUIT MEANS AND RESPONSIVE TO SAID TRIGGER PULSES FOR PREVENTING ACTUATION OF SAID FIRST CIRCUIT MEANS BY SUCCESSIVE ONES OF SAID TRIGGER PULSES AFTER A PRESELECTED TIME INTERVAL. 